Wellhead apparatus



Dec. 29, 1964 K. w. FOSTER ETAL 3,163,222

WELLHEAD APPARATUS 3 Sheets-Sheet 1 Filed April 24. 1961 FIG.

INVENTORS K. W. FOSTER J. A. HAEBER BY: I H77 fim AGENT 3 Sheets-Sheet 2 Dec. 29, 1964 K. w. FOSTER ETAL WELLHEAD APPARATUS Filed April 24, 1961 0 mm m W I M 7A/ 7 7 M A m w lmi m rd\\ \l in B I nu Cll W1 M w A 2 m F -YIIIIIIIIIIlIIIIIIIIIIIII/fl FIG.

INVENTORSI THEIR AGENT Dec. 29, 1964 K. w. FOSTER ETAL 3,163,222

WELLHEAD APPARATUS 3 Sheets-Sheet 5 Filed April 24. 1961 rw l nh H l llilllllu: HHHHHIIIIIIIII FIG. 48

FIG. 4A

INVENTORS:

K.W. FOSTER J. A. HAEBER BY: 1 7

EIR AGENT United States Patent 3,163,222 WELLHEAD APPARATUS Kenneth W. Foster and John A. Haeber, Houston, Tern, assigncrs to Shell Oil Company, New York, N.Y., a corporation of Delaware Filed Apr. 24, 1961, Ser. No. 105,068 6 Claims. (Cl. 16666.5)

This invention relates to apparatus for use on olishore wells and pertains more particularly to wellhead apparatus adapted to be securely locked on a well casinghead positioned underwater or on any other tubular member anchored beneath the surface of the water. The present invention is especially concerned with apparatus for remotely actuating a hydraulically operated wellhead connector apparatus which may be employed underwater for connecting two or more pieces of equipment together or for connecting a piece of equipment to a wellhead assembly.

In ,an attempt to locate new oil fields an increasing amount of well drilling has been conducted at olishore locations, such for example, as off the coast of Louisiana, Texas and California. As a general rule, the strings of casing in a well, together with the tubing strings or string, extend to a point above the surface of the water where they are closed in a conventional manner that is used on land wells, with a conventional wellhead assembly being attached to the top of the casing. Attempts have been made recently to provide methods and apparatus for drilling and completing a well wherein both the well casinghead and subsequently the wellhead assembly and casinghead equipment are located underwater at a depth sufiicient to allow ships to pass over them. Preferably, the casinghead and wellhead equipment are located close to the ocean floor. In order to install equipment of this type underwater in depths greater than the shallow depths at which a diver can easily operate, it has been necessary to design entirely new equipment for this purpose. Thus, during the drilling, completion and production of oil and gas wells at an otfshore location which have been drilled and completed in a manner described in copending patent application, Serial No. 830,538, filed July 30, 1959, and entitled Underwater Well Completion Method, various pieces of equipment may be remotely connected to the underwater wellhead by the wellhead connector of the present invention.

During the drilling of an underwater well it is generally necessary to connect various pieces of equipment such as blowout preventers or marine conductor pipes to a wellhead assembly situatedon the ocean floor. For this purpose a wellhead connector as described in copending application, Serial No. 830,533, filed July 30, 1959, may be employed. After the well has been drilled the wellhead equipment may be mounted on the top of the well casinghead and securely locked and sealed in place by means of the wellhead connector or lock-down apparatus described in copending patent application, Serial No. 834,096, filed August 17, 1959, now Patent No. 3,064,735.

The wellhead connectors described and illustrated in the above-identified patent applications comprise a connector housing having a vertical passage extending therethrough with a portion of the housing forming vertical wall means of a size to fit in close axially-slidable engagement with a tubular well member which is fixedly positioned in the well. The upper end of the tubular well member extends upwardly from the formation and is provided with latching grooves in one vertical wall thereof. The well connector apparatus is provided with hydraulically-actuatable locking dogs which are designed to be moved horizontally to engage the latching groove of the tubular well member to which the wellhead connector is being engaged.

3,153,222 Patented Dec. 29,1964

While hydraulically-operated equipment, such as wellhead connectors, have been found to be the most satisfactory for use on wellheads positioned underwater, they have the drawback of requiring at least two high-pressure hydraulic lines which must be of flexible construction and of suitable materials to extend from an underwater wellhead to a drilling base located at the surface of the water while at the same time being able to resist deterioration by sea water. The greater the number of hydraulicallyoperated devices that are employed at the wellhead, the more hydraulic lines that are needed to extend from the operating base above the water to the underwater wellhead. In one wellhead installation a group of 27 hydraulic lines were needed. These were formed in three bundles of nine each for ease of handling and to prevent them from becoming entangled. A single bundle of hydraulic lines may be ten inches in diameter and is Very cumbersome to handle.

It is therefore a primary object of the present invention to provide a wellhead connector apparatus provided with hydraulically-operated latching devices which are designed to be remotely operated by transmitting power through an electrical transmission line extending from an operating base above the surface of the water to the wellhead connector apparatus near the ocean floor.

A further object of the present invention is to provide a hydraulically-operated well connector assembly for connecting together two devices at a wellhead on the ocean floor without the need of hydraulic control lines running to the surface of the water.

Another object of the present invention is to provide a self-contained hydraulic system adapted to be positioned underwater to operate any of several hydraulically-actuatable devices normally employed at or on the wellhead assembly of an underwater well.

These and other objects of this invention will be understood from the following description taken with reference to the drawing, wherein:

FIGURE 1 is a diagrammatic View illustrating a floatable drilling barge anchored to the ocean floor over an underwater wellhead of a well being drilled;

FIGURES 2A and 2B are longitudinal views, taken in partial cross section, of one form of a wellhead connector assembly in accordance with the present invention which is equipped with a self-contained hydraulic pressure systern;

FIGURE 3 is a diagrammatic view of the hydraulic pressure system carried by the wellhead connector assembly of FIGURE 2 for operating the latching elements thereon; and

FIGURES 4A and 4B are longitudinal views taken in cross section of another form of a wellhead connector unit in accordance with the present invention.

Referring to FIGURE 1 of the drawing, a drilling barge ll of any suitable floatable type is illustrated as floating on the surface of a body of water 12 and substantially fixedly-positioned over a preselected drilling location, as by being anchored to the ocean floor by suitable anchors (not shown) at the ends of anchor lines 14 and 15. Equipment of this type may be used when carrying out well drilling, completion, or servicing operations in water varying from about feet to 1500 feet or more in depth. In shallower depths, instead of a floating barge, a barge having legs extensible downwardly to the ocean floor may be employed. A drilling barge is equipped with a suitable derrick 16 as well as other auxiliary equipment needed during the drilling, completion or maintenance of a well. The derrick 16 on the drilling barge is positioned over a drilling slot or a well 20 which extends vertically through the barge in a conventional manner. Well operations may also be carried out over the side of some barges without the use of a slot.

An equipment base assembly 17 forming a wellhead assembly is shown as being positioned on the ocean floor 13 and being anchored fixedly thereto bya conductor pipe The upper end of 22 and 23, only two being shown for ease of illustration.

During the drilling of a well .by the method disclosed in copending patent application, Serial No. 830,538, filed July 30, 1959, the wellhead installation may have attached thereto a wellhead connector assembly 24 which is fixedly attached in any suitable manner to a blow-out preventer 25 with the wellhead connector'24 being removably secured to the top of a well casing 21 forming thecasinghead 26. ,A second wellhead connector 27 is fixedly attached to the lower end of a marine conductor pipe 28,

with the wellhead connector 27 being removably secured to the top of the blow-out preventer 25' The marine conductor 28 is a large-diameter pipe extending upwardly from the wellhead to a point above the surface of the water at the barge 11. The wellhead connector 24, blow-out preventer 25 and wellhead connector 27 are provided with individual hydraulic systems contained in housings 31, 32, and 33, respectively, that are secured on the outside of their respective elements. Each of the the left-hand side of FIGURE 2. At this time the well head connector '24 would be fixedly locked on the casinghead 36. At the same time, an annular seal 54 carried by the housing forms a fluidtight seal between the well-' head connector 24 and the casinghead 36.

Fixedly secured on the wellhead connector 24 and carried thereby is an electric motor whose shaft 56 is operatively connected to drive a pair of pumps 57 and 58 through a pair of over-riding clutches 59 and 60. The.

over-riding clutches may be of any suitable design, such for example as those manufactured by Morse Chain Company, Ithaca, New York, Catalog No. SP-59, page 131, the clutches 59 and forming unidirectional drive assemblies mounted on the shaft between the motor and each of the pumps and arranged so that one pump operates or rotates when the motor turns in one direction and the other pump operates when the motor 55 reverses direction. Thus, it will be understood that only one pump 7 5'7 or 58 is operating at a time. The discharge ports 61 housings 31, 32 and 33 of the hydraulic operating systems has an electrical transmission cable or lead 34, 35 and 36 operatively connected thereto and extending to barge tending to the surface'where the leads 35 and 37 are connected to a suitable controller v325 or other operating circuitry. i

In one form of a casinghead 36, as shown in FIGURE 2, .a shoulder in the form ofa groove 41 is'provided -in at a 7 least a portion of the outer wall of the casinghead' 36,

preferably near the top thereof, to provide means for temporarily locking other equipment to the casinghead.

and 62 of pumps 57 and 58, respectively, are in fluid communication through a suitable piping circuit with pressure conduits 43 and 44. The entire hydraulic system is 'enclosed within a water-tight housing 31 through which electrical lead 34 extends.

One typical type of piping arrangement .is illustrated diagrammatically in FIGURE 3 wherein the intake ports of the pumps 57 and 58 are connected to a conduit which in turn is in communication with a reservoir tank 66 through conduit 67. The discharge conduits 70 and 71 from the pumps 57 and 5S, join to form a common conduit 72 which enters one port of a four-way valve 73. The four-way valve 73 is preferably of the rotary type as illustrated diagrammatically, but may be of any suitable type well known to the art, for example a piston and slide valve type. Two of the other ports of the four-way valve are connected to fluid conduits 43 and 44 while the fourth port is in fluid communication through conduit.

'74 with reservoir 66. Conduits 70 and 71 are provided With check valves or other unidirectional flow devices '75 and 76.

The four-way valve is provided with a hydraulic-operated valve operator diagrammatically shown as comprising a housing 77 having a piston 78 slidably mounted The wellhead connector 24 or 27 of FIGURE 1 may 7 i 7 take the form shown in FIGURE 2. In FIGURE 2, the

wellhead connector 24 is a hydraulically-operated seal-andlockdown head which is actuated by hydraulic pressure through pressure lines 43 and 44. The left-hand side of FIGURE 2 is shown with the well connector in its unlocked position while the right-hand side of FIGURE 2 shows the well connector in its locked position. T he wellhead'connector 24 comprises an annular housing 45 whose inner diameter is slightly larger than the outer diameter of the casinghead 36. The annular housing 45is provided with an annular chamber 46 in which there is mobably mounted an annular sleeve or piston 47 having a tapered face or shoulder 43 on the inside thereof.- The annular chamber-46 is alsoprovided with a plurality of locking therein, with a piston rod 79 extending therefrom and mechanically linked to the rotating four-way valve 73, as represented by the broken line 8t). One end of the valve operator housing 77 is in communication through conduit 83 with conduit 71 connected to the discharge of one pump 58, while the opposite end of the valve operator housing 77 is in fluid communication through conduit tend into the recessed portion 53 of the annular piston 47, a

being forced to this position when the wellhead connector S4 with the conduit 70 in communication with the dis,- charge ofthe other pump 57. The pumps 57 and 58 are preferably of the vane type or any other suitable type of pump. The electric motor 55 employed to drive the pumps 57 and 58 is a reversible motor, preferably a polyphase induction motor having no brushes which reduces the numberof elements in the underwater system that would be subject to failure Switching means would be provided in the controller 38 at the surface on the barge, so that the power inputto two of the leads of the motor 55 would be reversed in'order to reverse the motor. The reversing switch 94, diagrammatically represented by a box in FIGURE 3 may be of any suitable type well known to the art. Additionally, leads are preferably provided with suitable automatically reset trip switches 85 which may be either magnetic trip switches or thermal cut-out tripor. over-load switches.

In the operation of the present system, power would be supplied through electrical lead 34 from the barge to the motor 55 carried by the wellhead connector 24 (FIGURE 2). arranged so that the motor 55 (FIGURE 3) would run in a direction to operate pump 57 while the clutch 60 would over-ride and pump 58 would be stationary. Pres- The switching at the surface would besure fluid being discharged from the pump 57 would pass through conduit 70 and conduit 84 to force the piston 78 of the valve operator 77 in one extreme position, thus causing the four-way valve 73 to be turned to the position illustrated. Fluid from conduit 70 would then pass through check valve 75 and conduit 72 through valve 73 and conduit 43 into the upper end of the annular chamber 46 (FIGURE 2, right-hand side) so that the annular piston 47 would be forced downwardly and the locking dogs 49 would be forced into the groove 41 in the casinghead 36. A pressure of say 500 p.s.i. may be needed to start the piston 47 moving while a pressure of 1500 p.s.i. may be needed to force the piston to its final position. At the higher pressures at the end of the piston stroke a higher torque is generated by the motor 55 and the motor tries to stall causing more current to he demanded in the shut-off position, which demand causes the thermal or magnetic trip switches to open, thus shutting off the power to the motor 55. If desired, a pressure alarm transmitting device 85a of any suitable type may be provided in the system for electrically transmitting signals tothe surface as a safety precaution. An electrical lead from this device would join lead 34 and run to the surface. The reverse operation of the present apparatus wouldraise the piston and unlock the dogs 49. This is accomplished by reversing the phase rotation of the electric power to the motor 55, causing the motor 55 to run in the opposite direction. The motor operating in the opposite direction drives pump 58 whilethe clutch 59 would over-ride and pump 57 would be stationary. Pressure fluid being discharged from 'the pump 58 would pass through conduit 71 and 83 to force the piston 78 of the valve operator 77 in the other extreme position, thus causing the four-way valve 73 to be turned 90 degrees. Fluid from conduit 71 then would pass through check valve 76 and conduit 72, through valve 73 and conduit 44 into the lower end of the annular chamber 46 so that the piston 47 is forced upwardly, as shown in FIGURE 2, left-hand side.

Another form of the wellhead connector of the present invention is illustrated in FIGURE 4 wherein the wellhead connector is adapt'ed to fit within and sealingly latch onto the inner wall of a casing and tubing suspension mandrel 86 having a groove 87 formed on the inner surface thereof near the top thereof. The casing suspension mandrel may be seated within a casinghead 36 or may form an integral part thereof. The wellhead connector housing 45a is provided with an annular chamber 46a. An annular piston 47a is slidably positioned, being actuated by a pressure fluid being supplied through conduits 43a and 44a to drive the piston in one direction or the other. The wellhead connector body 45a is also provided with a series of outwardly extensible locking dogs 49a which are adapted to be forced outwardly into an annular groove 87 cut in the inner face of the casing suspension body or mandrel 86, upon downward movement of the piston 47a. The piston member 4711 is provided with a downwardly and inwardly sloping face 48a which forces the dogs into their locking position as shown 'on the right-hand side of FIGURE 4. The outer upper edges of the locking dogs 49a are preferably beveled, as at 88, whereby with the piston in its upper position, as shown on the left-hand side of FIGURE 2, the dogs 49a are retracted into the wellhead connector body 45a upon an upward pull of the wellhead connector body 45a with respect to the casing suspension mandrel or body 86. The operation of the wellhead connector body of FIG- URE 4 is similar to that previously described with regard to the arrangement of FIGURE 2 except that the locking dogs 49a of FIGURE 4 seat in the groove on the inner surface of a tubular member 87 while the locking dogs 49 of FIGURE 2 seat in an annular groove 41 in the outer surface of a tubular member, as illustrated. Additionally, the seal 54a of FIGURE 4 seals against the inner surface of the tubular member 86 while in FIG- URE 2 the seal 54 seals against the outer surface of the tubular member 36. The wellhead connector of FIG- URE 4 may be provided with a motor 551: for driving a pair of pumps 57a and 58a alternately and selectively by means of a hydraulic system similar to that described with regard to FIGURE 3 hereinabove. The present hydraulic system may be used to operate the rams of a blow-out preventer 35 or to operate hydraulic valves in an underwater production wellhead.

We claim as our invention:

1. In apparatus for drilling, servicing and producing a well underlying a body of water wherein at least a portion of the well equipment has been fixedly positioned in the well with the upper end of a tubular well member extending upwardly from the formation and latch receiving shoulder means formed on one vertical wall thereof, a wellhead connector assembly comprising a housing having a passage extending vertically therethrough, a portion of said housing forming vertical wall means of a size to fit in close axially-slidable engagement with said tubular well member, seating shoulder means carried by said housing for engagement and resting on a landing surface formed on said tubular well member, hydraulicallyactuatable locking dog means carried by said housing in a normally inoperative manner for registering with said latch receiving means of said tubular well member, said locking dog means being extensible into and out of engagement with said latch receiving means, piston-type actuating means carried by said housing and operatively engaging said locking dog means for actuating said dog means, pressure-fluid conduits through said housing to opposite sides of said actuating means, each of said conduits being in communication with the discharge port of one of a pair of pumps mounted on said housing, electric motor means having shaft means connected to said two pumps and mounted on said housing adjacent said pumps, a pressure-fluid reservoir mounted on said housing, supply conduit means in communication between said reservoir and intake ports of said pumps, flow control valve means in said conduit means between said pumps and said piston means and said reservoir, said valve being arranged to put selectively one pump and the reservoir in communication with the conduits to opposite sides of the pistonmeans and then the other pump and the reservoir in communication with opposite and difierent sides of said piston means, check valves in said conduits from said pumps, hydraulically-operated valve actuator means in pressure communication with both of said pumps and being operatively connected to said flow control valve means, power leads to said motor means extending to above the surface of the body of water, and switching means in said power leads at a point above said body of water.

2. In apparatus for drilling, servicing and producing a Well underlying a body of water wherein at least a portion of the well equipment has been fixedly positioned in the well with the upper end of a tubular well member extending upwardly from the. formation and latch receiving means formed on one vertical wall thereof, a wellhead connector assembly comprising a housing having a'passage extending vertically therethrough, a portion of said hous-v ing forming vertical wall means of a size to fit in close axially-slidable engagement with said tubular well mem-- ber, seating shoulder means carried by said housing for engagement and resting on a landing surface formed on said tubular well member, hydraulically-actuatable locking dog means carried by said housing in a normally inoperative manner in recesses formed in the wall of said housing adjacent the vertical wall portion of said tubular well member and in register with said latch receiving means therein, said locking dog means being radially and horizontally-extensible into and out of engagement with said latch receiving means, piston means carried by said housing and operatively engaging said locking dog means for actuating said dog means, pressure-fluid conduits through said housing to opposite sides of said piston 7 means, each of said conduits being in communication with the discharge port of one of a pair of pumps mounted on said housing, a reversible electric motor having opposite ends of its shaft connected to said two pumps and mounted on said housing adjacent said pumps, unidirec pumps and said piston means and said reservoir, said.

valve being arranged 'to put selectively one pump and the reservoir in communication with the conduits to opposite sides of the piston" means and then the other' pump and the reservoir in communication with opposite and different sides of said piston means, check valves in said conduits from said pumps, hydraulically-operated 'valve actuatormeans in pressure communication with both of said pumps and being operatively connected to said flow control valve means, power leads to said motor extending to above the surface of the body of water, and switchingmeans in said powerrleads at a point above said bod-y of water.

3. In apparatus for drilling,sservicing and producing a well underlying a body of water wherein at least a portion of the well equipment has been fixedly positioned in the well with the upper end of a,=tubular well member extending upwardly from the formation and latching groove means formed in one vertical wall thereof, a wellhead connector assembly comprising a housing having a passage extending vertically therethrough, a portion of said housing forming vertical wall means of a size to fit in close axially-,slidable engagement with said tubular' well member, seating shoulder means carried by said housing for engagement and resting on a landing surface at a point above said body of water, and breaker switches in said power leads for shutting 01f operating current to said motor when said piston means has been moved to one of its extreme positions.

4. An underwater wellhead assembly mounted on a well casing extending downwardly into an earth formation covered by a body of water said wellhead assembly including a wellhead connector device having a housing removably secured to said assembly, chamber means in said housing, substantially fiuidtight movable barrier means mounted in said chamber means, movable means carried bysaid housing and operatively-engaging said movable barrier means, pressure-fluid conduits through said housing to, opposite sides of said movable barrier,

, communication with the conduits to opposite sides of the movable barrier means and then the other pump and the reservoir in communication with opposite and different sides of said movable barrier means, check valves in said conduits from said pumps, hydraulically-operated valve actuator means in pressure communication with both of said pumps and being operatively connected to said flow control valve means, power leads to said motor means extending to' above the surface of the body of water, and reversing switching means in said power leads at a point above said body of water.

5. An underwater wellhead assembly mounted on a well casing extending downwardly into an earth formation covered by a body of water said wellhead assembly including a wellhead connector device having a housing removably secured to said assembly, piston chambermeans in said housing, movable piston means mounted in said chamber means, movable casing-engaging means said locking dog means for actuating said'dogmeans to at least a locked position, pressure-fluid conduits through'said housing to opposite sides of said piston means, each of said conduits being in communication'with the discharge port of one ofa pair of pumps mounted on said housing, .a reversible electric motor having oppo- .7 said reservoir and intake ports of said pumps, four-way flow control valve means in said conduit means between said pumps and said pistonmeans and said reservoir, said valve being arranged to put selectively one pump and the reservoir in communication with the conduits to opposite sides of the piston means and then the other pump and the reservoir in communication with opposite and different sides of said piston means, check valves in said conduits from said pumps, hydraulically-operated pistontype valve actuator means in pressure communication with both of said pumps and being operatively connected to said four-way flow control .Valve means, power leads to said motor extending to above the surface of the body of water, reversible switching means in said power leads carried by said housing and operatively-connected to said movable piston means, pressure-fluid conduits through said housing to opposite sides of said movable piston means, each of said conduits being in communication with the discharge port of one of a pair of pumps mounted on said housing, a reversible electric motor having opposite. ends of its shaft connected to said two pumps and mounted on said housing adjacent said pumps, unidirectional clutch means mounted in said shaft between said motor'and each of said pumps and arranged so that one pump operates when the motor turns in one direction tively one pump and the reservoir in communication with the conduits to opposite sides of the movable piston means andtthen the other pump and the reservoir in communication with opposite and different sidesof said movable piston means, check valves in said conduits from said pumps, hydraulically-operated valve actuator means in pressure communication with both of said pumps and being operatively connected to said four-way flow control valve means, power leads to said motor extending to above the surface of the body of water, reversible switching means in said power leads at a point above said body of water.

6. The apparatus of claim 5 including breaker switches in said power leads for shutting otf operating current to 9 10 said motor when said piston means has been moved to 3,063,507 11/62 ONeill et a1. 166-665 one of its extreme positions. 3,064,735 11/62 Bauer et-al 16666.5

FOREIGN PATENTS References Clted by the Exammer 5 160,865 4/21 Great Britain. UNITED STATES PATENTS 814,520 6/59 Great Britain. 2,614,803 10/52 \Viggins 175 s X 874,178 8/61 Great Brltam- 2,872,940 2/59 Lewis 137554 CHARLES E. OCONNELL, Primary Examiner. 

4. AN UNDERWATER WELLHEAD ASSEMBLY MOUNTED ON A WELL CASING EXTENDING DOWNWARDLY INTO AN EARTH FORMATION COVERED BY A BODY OF WATER SAID WELLHEAD ASSEMBLY INCLUDING A WELLHEAD CONNECTOR DEVICE HAVING A HOUSING REMOVABLY SECURED TO SAID ASSEMBLY, CHAMBER MEANS IN SAID HOUSING, SUBSTANTIALLY FLUIDTIGHT MOVABLE BARRIER MEANS MOUNTED IN SAID CHAMBER MEANS, MOVABLE MEANS CARRIED BY SAID HOUSING AND OPERATIVELY-ENGAGING SAID MOVABLE BARRIER MEANS, PRESSURE-FLUID CONDUITS THROUGH SAID HOUSING TO OPPOSITE SIDES OF SAID MOVABLE BARRIER MEANS, EACH OF SAID CONDUITS BEING IN COMMUNICATION WITH THE DISCHARGE PORT OF ONE OF A PAIR OF PUMPS MOUNTED ON SAID HOUSING, REVERSIBLE ELECTRIC MOTOR MEANS HAVING A SHAFT CONNECTED TO SAID TWO PUMPS AND MOUNTED ON SAID HOUSING ADJACENT SAID PUMPS, A PRESSURE-FLUID RESERVOIR MOUNTED ON SAID HOUSING, SUPPLY CONDUIT MEANS IN COMMUNICATION BETWEEN SAID RESERVOIR AND INTAKE PORTS OF SAID PUMPS, FLOW CONTROL VALVE MEANS IN SAID CONDUIT MEANS BETWEEN SAID PUMPS AND SAID MOVABLE BARRIER MEANS AND SAID RESERVOIR, SAID VALVE MEANS BEING ARRANGED TO PUT SELECTIVELY ONE PUMP AND THE RESERVOIR IN COMMUNICATION WITH THE CONDUITS TO OPPOSITE SIDES OF THE MOVABLE BARRIER MEANS AND THEN THE OTHER PUMP AND THE RESERVOIR IN COMMUNICATION WITH OPPOSITE AND DIFFERENT SIDES OF SAID MOVABLE BARRIER MEANS, CHECK VALVES IN SAID CONDUITS FROM SAID PUMPS, HYDRAULICALLY-OPERATED VALVE ACTUATOR MEANS IN PRESSURE COMMUNICATION WITH BOTH OF SAID PUMPS AND BEING OPERATIVELY CONNECTED TO SAID FLOW CONTROL VALVE MEANS, POWER LEADS TO SAID MOTOR MEANS EXTENDING TO ABOVE THE SURFACE OF THE BODY OF WATER, AND REVERSING SWITCHING MEANS IN SAID POWER LEADS AT A POINT ABOVE SAID BODY OF WATER. 